class CombineItemsInCart < ActiveRecord::Migration
  def up
  	Cart.all.each do |cart|
  		sums=cart.line_items.group(:product_id).sum(:quantity)

  		sums.each do |product_id, quantity|
  			if quantity>1
  				cart.line_items.where(:product_id=>product_id).delete_all

  				cart.line_items.create(:product_id=>product_id, :quantity=>quantity)
  			end
  		end
  	end
  end

  def down
  end
end
